不等式8/X^-9
问题描述：
不等式8/X^-9
数学人气：756 ℃时间：2020-07-03 04:05:08
优质解答
|x|>0
所以8|x|/(x^2-9)(8|x|-x^2+9)/(x^2-9)(x^2-8|x|-9)/(x^2-9)>=0
x则(x^2+8x-9)/(x^2-9)>=0
(x+9)(x-1)/(x+3)(x-3)>=0
x=3
且x所以xx>0
则(x^2-8x-9)/(x^2-9)>=0
(x-9)(x+1)/(x+3)(x-3)>=0
x=9
且x>0,分母不等于0
所以0
所以8|x|/(x^2-9)(8|x|-x^2+9)/(x^2-9)(x^2-8|x|-9)/(x^2-9)>=0
x则(x^2+8x-9)/(x^2-9)>=0
(x+9)(x-1)/(x+3)(x-3)>=0
x=3
且x所以xx>0
则(x^2-8x-9)/(x^2-9)>=0
(x-9)(x+1)/(x+3)(x-3)>=0
x=9
且x>0,分母不等于0
所以0
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答
|x|>0
所以8|x|/(x^2-9)(8|x|-x^2+9)/(x^2-9)(x^2-8|x|-9)/(x^2-9)>=0
x则(x^2+8x-9)/(x^2-9)>=0
(x+9)(x-1)/(x+3)(x-3)>=0
x=3
且x所以xx>0
则(x^2-8x-9)/(x^2-9)>=0
(x-9)(x+1)/(x+3)(x-3)>=0
x=9
且x>0,分母不等于0
所以0